I like that this challenges some assumptions, but it does very little to discredit the AMPLE research in the area. Other than to say, let's not trust old research, which is kind of a gas-lighty way to look at it.
The issue is, when its the police who determine whether someone is acting correctly, it's trivial for them to do this, as they can just rule that they were right and the protesters were wrong. The video from the Seattle protest yesterday was a great example of this. Fuck the police.